NSOperation和NSOperationQueue的一些基本操作

当初学习多线程这一块的时候，时间比较匆忙，没有细细考虑，而今重新学一次，算是复习和总结吧。

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

/*
 通过调用[self invocationOperation]的log，可以发现，在不加入queue的情况下，默认是在主线程中同步执行操作的
 
 而通过调用[self blockOperation]的log，可以发现，在不加入queue的情况下，同一个block里的任务是，默认是在主线程中同步执行操作的。但是，如果有多个block操作，会是并发、异步执行的
 
 NSBlockOperation 可以设置监听，调用[self opeationListen]  在完成任务后，可以设置完成这个任务想要执行的操作
 
 调用[self operationQueue]的log，可以发现，在不设置依赖的情况下，任务是并发、异步执行的
 
 而设置依赖的情况下，设置了依赖的任务按照所设定的顺序调用，而没有设置的，则是并发、异步执行
 */
- (void)viewDidLoad {
    [super viewDidLoad];
    
    [self opeationListen];
}

- (void)invocationOperation
{
    NSInvocationOperation *invocation = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(downLoadImage) object:nil];
    [invocation start];
}

- (void)blockOperation
{
    NSBlockOperation *blockOperation = [[NSBlockOperation alloc] init];
    
    [blockOperation addExecutionBlock:^{
        for (int i = 0; i<10; i++) {
            NSLog(@"blockOperation------下载图片1---%@", [NSThread currentThread]);
            [NSThread sleepForTimeInterval:0.1];
        }
    }];
    
    [blockOperation addExecutionBlock:^{
        NSLog(@"blockOperation__2 --- %@",[NSThread currentThread]);
    }];
    
    [blockOperation addExecutionBlock:^{
        NSLog(@"blockOperation__3 --- %@",[NSThread currentThread]);
    }];
    
    [blockOperation start];
}

- (void)opeationListen
{
    NSBlockOperation *blockOperation = [NSBlockOperation blockOperationWithBlock:^{
        for (int i = 0; i<10; i++) {
            NSLog(@"opeationListen------下载图片---%@", [NSThread currentThread]);
        }
    }];
    
    blockOperation.completionBlock = ^{
        // ...下载完图片后想做事情
        NSLog(@"NSBlockOperation------下载图片完毕---%@", [NSThread currentThread]);
    };
    
    [blockOperation start];
}

- (void)downLoadImage
{
    for (int i = 0; i < 10; i++) {
        NSLog(@"downLoadImage----正在下载----image---%@",[NSThread currentThread]);
        [NSThread sleepForTimeInterval:0.2];
    }
}

- (void)run
{
    for (int i = 0; i<10; i++) {
        NSLog(@"run---正在跑步-----%@", [NSThread currentThread]);
        [NSThread sleepForTimeInterval:0.2];
    }
}
- (void)operationQueue
{
    NSInvocationOperation *invocationOperation_1 = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(downLoadImage) object:nil];
    
    NSInvocationOperation *invocationOperation_2 = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(run) object:nil];
    
    NSBlockOperation *blockOperation_1 = [NSBlockOperation blockOperationWithBlock:^{
        for (int i = 0; i < 10; i++) {
            NSLog(@"blockOperation_1------下载图片---%@", [NSThread currentThread]);
            [NSThread sleepForTimeInterval:0.1];
        }
    }];
    
    NSBlockOperation *blockOperation_2 = [NSBlockOperation blockOperationWithBlock:^{
        for (int i = 0; i < 10; i++) {
            NSLog(@"blockOperation_2------下载视频---%@", [NSThread currentThread]);
            [NSThread sleepForTimeInterval:0.1];
        }
    }];
    
    //设置依赖
    [blockOperation_2 addDependency:blockOperation_1];
    
    NSOperationQueue *queue = [[NSOperationQueue alloc] init];
    
    //设置最大并发数（一般设置为2~~3个）
    queue.maxConcurrentOperationCount = 3;
    
    [queue addOperations:@[invocationOperation_1, invocationOperation_2, blockOperation_1, blockOperation_2] waitUntilFinished:NO];
}
@end